Insulin-like growth factor I increases bone formation in old or corticosteroid treated rats.
We studied bone induction in subcutaneous implants of demineralized bone matrix with or without insulin-like growth factor I (IGF-I) in aged or corticosteroid-treated rats. Each rat carried one pair of implants, one control and one experiment implant, containing IGF-I dissolved in a hyaluronan solution for slow release. The rats were killed after 3 weeks and the results were evaluated by measuring the calcium content of implants. Young (6-7 weeks) and old (19-27 months) rats were used. A group of young rats was treated for 1 week with subcutaneous injections of 140 micrograms/kg dexamethasone daily. Old rats produced only approximately 1% as much bone as young rats. Local delivery of IGF-I did not increase bone formation in young rats. In old rats, bone formation was increased by IGF-I, 3000 ng/implant. Corticosteroids reduced bone formation in young rats. This effect was partially reversed by local administration of IGF-I.
Prisell
P T
PT
Department of Orthopedic Surgery, Novum, Huddinge University Hospital, Sweden.
Aspenberg
P
P
Wikström
B
B
Wredmark
T
T
Norstedt
G
G
D000367:Age Factors; D000818:Animals; D018775:Bone Demineralization Technique; D018786:Bone Substitutes; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D020007:Implants, Experimental; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins
D018786:Bone Substitutes; D005938:Glucocorticoids; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone